The impact of potassium humate, ammonium humate and vermicompost tea on the root-knot nematode, Meloidogyne arenaria, and their effect on plant growth and some biochemical parameters in eggplant were determined in vitro and in vivo. The in vitro results showed that egg hatching and juvenile mortality of M. arenaria were significantly (P ≤ 0.05) affected by treatments. Ammonium humate 3 and 2% were more effective in inhibiting egg hatching after 4 days by 61.6 and 82.6% respectively. Also, in ammonium humate 3%, the increase of exposure period from 24 to 48 hrs. raised mortality from 73.3 to 82%. In vivo experiment treatments were applied under greenhouse conditions with two different application methods (soil drenching, and foliar spray) and two concentrations (2 and 3%) on the root-knot nematode, M. arenaria population, and their impact on eggplant. All tested treatments significantly decreased nematode number to different levels compared to control. The highest suppression in total nematode population was recorded with drenching by 3% ammonium humate. A similar trend was noticed with reproduction factor and number of galls or egg- masses per root system. Plants grown in soil drenched by 3 % ammonium humate recorded the highest value in fresh and dry weight, as well as shoot and root length. Also, these plants gave the highest values of carotenoids, phenolic compounds and total amino acids. While, the highest value of proline content appeared with control. Also, the results showed that the total chlorophyll, total protein and reducing sugar content increased in all treatments compared to control.